TypeGraphQL

Motivation

We all know that GraphQL is so great and solves many problems that we have with REST API, like overfetching and underfetching. But developing a GraphQL API in Node.js with TypeScript is sometimes a bit of pain. Why? Let's take a look at the steps we usually have to make.

At first, we create the all the schema types in SDL. We also create our data models using ORM classes, which represents our db entities. Then we start to write resolvers for our queries, mutations and fields, but this forces us to first create TS interfaces for all arguments, inputs, and even object types. Only then can we actually implement the resolvers, using weird generic signatures, e.g.:

The biggest problem is the redundancy in our codebase, which makes it difficult to keep things in sync. To add a new field to our entity, we have to jump through all the files - modify an entity class, the schema, as well as the interface. The same goes with inputs or arguments. It's easy to forget to update one piece or make a mistake with a single type. Also, what if we've made a typo in field name? The rename feature (F2) won't work correctly.

TypeGraphQL comes to address this issues, based on experience from over a dozen months of developing GraphQL APIs in TypeScript. The main idea is to have only one source of truth by defining the schema using classes and a bit of decorator help. Additional features like dependency injection, validation or auth guards helps with common tasks that normally we would have to handle by ourselves.

Introduction

As I mentioned, TypeGraphQL makes developing a GraphQL API and enjoyable process, i.e. by defining the schema using only classes and a bit of decorator magic.

So, to create types like object type or input type, we use kind of DTO classes.
For example, to declare Recipe type we simply create a class and annotate it with decorators:

Then we can create queries, mutations and field resolvers.
For this purpose we use controller-like classes that are called "resolvers" by convention.
We can also use awesome features like dependency injection or auth guards:

Examples

You can also check the examples folder on this repository for more examples of usage: simple fields resolvers, DI Container support, TypeORM integration, automatic validation, etc.

The Tests folder might also give you some tips how to get various things done.

Work in progress

Currently released version is a MVP (Minimum Viable Product).
It is well tested (95% coverage, 4400 lines of test code) and has 90% of the planned features already implemented.
However there's some work to do before 1.0.0 release and it's mostly about documentation (website, api reference and jsdoc).

I encourage you to give it a try and experiment with TypeGraphQL. If you have any question, you can ask about it on gitter. If you find a bug, please report it as an issue on GitHub. If you have an interesting feature request, I will be happy to hear about it.

Contribution

PRs are welcome, but first check, test and build your code before committing it.